Thin and lightweight is a prevailing design trend for electronic products these days. Likewise, there is no point to have small components housed in a bulky product. Therefore all aspects of an electronic product should focus these design issues. Mating switch design is no exception. A slimmer design needs to maintain existing compression displacement so as not to affect the feeling of depressing a button. Refer to FIG. 1 for a patent granted to Applicant in ROC patent No. 367086, entitled “Improved touch switch”. It comprises a seat made from an insulating material. The seat has a hollow housing with an opening on the upper side. There is a first conductive electrode located in the center of the housing. There are two second conductive electrodes located on two sides of the housing. A fastening section is located on the outer side of the seat. There is an elastic dome reed made of a conductive thin metal sheet. The elastic dome reed has a peripheral section and a protrusive section which gradually extends upwards from the peripheral section to the center. The peripheral section is in contact with the second conductive electrodes of the seat. The protrusive section is spaced from the first conductive electrode over a selected distance. When the elastic dome reed is subject to a downward force as the button is pressed, it touches the first conductive electrode. When the pressure is released, the elasticity restores. A trigger member is located above the elastic dome reed that includes an upper button made from plastic with a recess on the bottom, and a lower button made from rubber. The lower button has a jutting section on the top corresponding to and coupling tightly with the recess of the upper button. The lower button is in contact with the center area of the elastic dome reed. A cap which has an opening on the upper side and two anchor sections on two sides is provided to couple with the seat from the outer side. The anchor sections are latched on a fastening section of the seat to confine the elastic dome reed and the trigger member in the seat. The upper button of the trigger member is extended outside the opening of the cap. The aforesaid reference provides a lasting smooth surface for the upper button, and the rubber lower button is pliable and in contact with the elastic dome reed to enable the touch switch to function as desired. FIG. 2 illustrates another ROC patent No. 378332, entitled “Pushbutton switch”. It differs from the previous reference by having a lower jutting section extended from an elastic driving member (lower button) to increase the displacement.
The two aforesaid references have a flat section and a lower jutting section on the lower button. Such designs are unnecessary for this type of switch, and do not really contribute to the compression displacement. As a result, they are restricted to a certain height and cannot be made thinner. Their applicability to present electronic products is limited.